Quality of service architecture for home mesh network

ABSTRACT

An embodiment is a technique to perform QoS. An interface between an upper layer and a lower layer in a multi-hop mesh network receives and transmits packets from and to a local node and a remote node. A classifier classifies the received packets into a plurality of packet types having different priority levels. A queue manager manages a plurality of buffers organized according to the packet types. The plurality of buffers stores the classified packets based on the packet types. A scheduler schedules distributing the packets from the plurality of buffers based on the priority levels according to a scheduling policy.

TECHNICAL FIELD

The presently disclosed embodiments are directed to the field ofwireless communication, and more specifically, to mesh network.

BACKGROUND

A wireless network can provide a flexible data communication system thatcan either replace or extend a wired network. Using radio frequency (RF)technology, wireless networks transmit and receive data over the airthrough walls, ceilings and even cement structures without wiredcabling. For example, a wireless local area network (WLAN) provides allthe features and benefits of traditional LAN technology, such asEthernet and Token Ring, but without the limitations of being tetheredtogether by a cable. This provides greater freedom and increasedflexibility.

Currently, a wireless network operating in accordance with the Instituteof Electrical and Electronic Engineers (IEEE) 802.11 Standard (e.g.,IEEE Std. 802.11a/b/g/n) may be configured in one of two operatingmodes: infrastructure mode and ad hoc mode. One important aspect ofwireless communication is Quality of Service (QoS). Traditional QoStechniques focus on single-hop network and are typically implemented ona single device (e.g., a router or a server) in the network. Thesetechniques are not suitable for multiple hop distributed networks. Inaddition, existing QoS techniques typically do not discriminatedifferent levels of media qualities such as high-definition (HD) andstandard definition (SD) videos.

SUMMARY

One disclosed feature of the embodiments is a method and apparatus toperform QoS. An interface between an upper layer and a lower layer in amulti-hop mesh network receives and transmits packets from and to alocal node and a remote node. A classifier classifies the receivedpackets into a plurality of packet types having different prioritylevels. A queue manager manages a plurality of buffers organizedaccording to the packet types. The plurality of buffers stores theclassified packets based on the packet types. A scheduler schedulesdistributing the packets from the plurality of buffers based on thepriority levels according to a scheduling policy.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments may best be understood by referring to the followingdescription and accompanying drawings that are used to illustrateembodiments. In the drawings.

FIG. 1 is a diagram illustrating a system of a three-tier wireless adhoc home mesh network (WHMN) according to one embodiment.

FIG. 2 is a diagram illustrating a mesh QoS architecture according toone embodiment.

FIG. 3 is a flowchart illustrating a process to provide a QoS for themesh network according to one embodiment.

FIG. 4 is a diagram illustrating a classifier according to oneembodiment.

FIG. 5 is a flowchart to illustrate a process to classify a packetaccording to one embodiment.

FIG. 6 is a flowchart to illustrate a process to classify a packetaccording to one embodiment.

FIG. 7 is a flowchart to illustrate a process to classify a packetaccording to one embodiment.

FIG. 8 is a flowchart to illustrate a process to analyze the applicationheader according to one embodiment.

FIG. 9 is a flowchart to illustrate a process to update the dynamic porttable according to one embodiment.

FIG. 10 is a diagram illustrating a queue manager according to oneembodiment.

FIG. 11 is a flowchart illustrating a process to perform queuemanagement according to one embodiment.

FIG. 12 is a flowchart illustrating a process to receive according toone embodiment.

FIG. 13 is a flowchart illustrating a process to enqueue according toone embodiment.

FIG. 14 is a diagram illustrating a scheduler according to oneembodiment.

FIG. 15 is a flowchart illustrating a process to schedule according toone embodiment.

FIG. 16 is a flowchart illustrating a process to visit the buffersaccording to one embodiment.

FIG. 17 is a flowchart illustrating the process 1520 to dequeue thebuffers according to one embodiment.

FIG. 18 is a diagram illustrating a processing system to perform the QoSaccording to one embodiment.

DETAILED DESCRIPTION

One disclosed feature of the embodiments is a technique to perform QoS.An interface between an upper layer and a lower layer in a multi-hopmesh network receives and transmits packets from and to a local node anda remote node. A traffic classifier classifies the received packets intoa plurality of packet types having different priority levels byrecognizing their application type. A queue manager manages a pluralityof buffers organized according to the packet types or their prioritylevels. The plurality of buffers stores the classified packets based onthe packet types. A packet transmission scheduler schedules distributingthe packets from the plurality of buffers based on the priority levelsaccording to a scheduling policy. This interface also receives andclassifies forwarded packets received by the lower layer transmitted bya neighboring node.

In the following description, numerous specific details are set forth.However, it is understood that embodiments may be practiced withoutthese specific details. In other instances, well-known circuits,structures, and techniques have not been shown to avoid obscuring theunderstanding of this description.

One disclosed feature of the embodiments may be described as a processwhich is usually depicted as a flowchart, a flow diagram, a structurediagram, or a block diagram. Although a flowchart may describe theoperations as a sequential process, many of the operations can beperformed in parallel or concurrently. The beginning of a flowchart maybe indicated by a START label. The end of a flowchart may be indicatedby an END label. In addition, the order of the operations may bere-arranged. A process is terminated when its operations are completed.A process may correspond to a method, a program, a procedure, a methodof manufacturing or fabrication, etc. One embodiment may be described bya schematic drawing depicting a physical structure. It is understoodthat the schematic drawing illustrates the basic concept and may not bescaled or depict the structure in exact proportions.

FIG. 1 is a diagram illustrating a system of a three-tier wireless adhoc home mesh network (WHMN) according to one embodiment.

Multi-tier wireless home mesh network 100 (hereinafter referred to as“WHM network” or “WHMN” 100) comprises a collection of nodes thatoperate as a decentralized, wireless home mesh network with multiple(N≧1) sub-networks 111 ₁-110 _(N) (hereinafter singularly referred to as“tiers”) that are responsible for different functions within WHM network100. Hence, mostly every node of WHM network 100 is configured toforward data to other nodes and is assigned to a specific tier based onits performance capabilities and power constraints. The assignment of anode to a tier is a decision based on performance capabilities of thenode, whereas routing decisions are made by the nodes based on thenetwork connectivity and the ability to forward data by that particularnode.

For instance, one embodiment of WHM network 100 features a hierarchicalarchitecture comprising three (3) tiers that are assigned based on thecapabilities of the node. A first tier (“tier 1”) 110 ₁ is responsiblefor establishing and controlling access to an external network such asthe Internet. For example, first tier 110 ₁ may resemble a traditionalInternet connection via a cable or direct subscriber line (DSL)connection or 3G/WiMax/Outdoor mesh. As illustrated, first tier 110 ₁comprises a first node 120, which is commonly referred to as a “gatewaynode.” Gateway node 120 may include, but is not limited or restricted toa cable or DSL modem, a wireless router or bridge, and the like.Although not shown, multiple gateway nodes may be present within WHMnetwork 100 in order to provide multiple communication paths to externalnetwork(s).

A second tier (“tier 2”) 110 ₂ of WHM network 100 may represent awireless network backhaul that interconnects various stationary(fixed-location) wireless nodes such as stationary (fixed-location)electronics devices adapted for communicating over a wirelesscommunication medium such as, for example, radio frequency (RF) waves.As described herein, an “electronic device” may be stationary or mobile.A “stationary electronics device” includes, but is not limited orrestricted to: a flat-panel television (130, 131, and 132), a gamingconsole (140), desktop computer (150), or any other device that isusually stationary and is electrically coupled to an AC power outlet.Hence, stationary electronics devices are not subject to powerconstraints that are usually present in mobile nodes where power usageis minimized to extend battery life between recharges.

A third tier (“tier 3”) 110 ₃ of WHM network 100 may include linksbetween a wireless node belonging to second tier 110 ₂ and one or moremobile nodes (160, 162, 164, 166, 168 & 169). A “mobile node” mayinclude any battery powered electronics device with wirelessconnectivity including, but is not limited to a laptop computer,handheld device (e.g., personal digital assistant, ultra mobile device,cellular phone, portable media player, wireless camera, remote control,etc.) or any non-stationary consumer electronics devices. Since mobilenodes normally have resource constraints (e.g., limited power supplies,limited processing speeds, limited memory, etc.), third tier 110 ₃ mayprovide reduced network services. In one embodiment, mobile nodes of WHMnetwork 100 may act as a slave or child connecting directly to a tier-2node, which may further limit their functionality within WHM network100.

Table 1 summarizes a multi-tier, wireless home mesh networkarchitecture, categorization by potential network characteristics, tiernode descriptions and traffic type that is prevalent over WHM network100.

TABLE 1 multi-tier wireless home mesh network scenario CharacteristicsExamples Network Dimension ~50 × 60 sq ft; House 1-2 stories or high-Apartment building rising building Business Node Number Tier 2 - 3~10; 2TVs, 1 desktop Tier 3 - 5~20 computer, 1 PS3; 2 laptops, 4 mobilephones, 4 media players, . . . Distribution Indoor, 3D, Non- UniformlyLOS, link distance distributed Tier-2 15~60 ft nodes, clustered Tier 3Node Tier 1 Usually one or two Cable/DSL modem, Type Tier 1 nodesWiMax/3G, (per Tier Outdoor Mesh Network) Tier 2 Fixed location, TV,desktop power-sufficient computer, gaming (TX power console (e.g. PS3),100 mW-1 W) etc. Tier 3 Mobile, power- Laptop, mobile limited (TX powerphone, portable 1-100 mW) media player, wireless camera, remote TrafficHD video ~30 Mbps 1080p/i, 720p/i, streaming compressed 480p/i qualityHD videos SD Video/Audio ~100k-1 Mbps Internet video clip streamingvideo, 32k-256 kbps (e.g. YouTube ®), audio webcam output, mp3 audio,voice Data Bursty http type data (web transmission, browsing) ~20 Mbpsfor certain user satisfaction

As indicated by Table 1, WHM network 100 is distinct from conventionalmesh-network solutions because WHM network 100 is directed to consumerelectronics (CE) devices and video-centric applications. Based on thetraffic indicated in Table 1, which may include high-definition (HD)video, audio clips and video clips, as well as user data, wireless NICsmay be incorporated within some of the stationary nodes of the WHMnetwork 100. For example, by multiplexing one flow of compressed HDvideo, four Internet video sessions plus four audio/video sessions andsome intermittent http data traffic, the load on the backhaul link 170is approximately 60 megabits per second for TCP/UDP type traffic, whichmay require at least 100 megabits per second of raw radio supportconsidering media access control (MAC) layer efficiency. According tothis example, the tier 2 nodes might require an 802.11n type radio(e.g., at 5 GHz band) to meet such a bandwidth requirement.

The WHMN 100 represents a network in which a mesh backhaul includingfixed nodes such as TVs, desktop computers and Play stations. There maybe many high-bandwidth demanding applications and low-bandwidthapplications. A QoS architecture is needed to provide service andsupport for mixed video, audio, and data applications.

Mesh QoS Design Architecture:

In one embodiment, the QoS design is based on the distinction amongdifferent types of traffic streams. The mesh network may be targeted toTV-centric home scenarios where fixed and mobile devices may beconnected by the TV-based network architecture. The traffic streams mayrepresent a variety of content formats or types. For example, thetraffic streams going through the television may be video streams.Within the video streams, there may be a number of different formats,such as high definition (HD) or standard definition (SD). Within the HDtypes, there may be different levels of resolution. For example, the HDmay include 1080 progressive/interlaced (p/i), 720 p/i, 480 p/i. Whenthe television is connected to a computer or data network (e.g., theInternet), the video streams for normal TV viewing may compete withother network-based traffic streams such as premium video content, smallvideo clips, and Web data. These content streams may have differentbandwidths, delays, types of services, and priority levels. A useful QoSdesign, therefore, aims at distinguishing the types of content streamsso that appropriate services may be provided.

FIG. 2 is a diagram illustrating a mesh QoS architecture 200 in a localnode according to one embodiment. The mesh QoS architecture 200 includesan application layer 210, a Transmission Control Protocol/InternetProtocol (TCP/IP) layer 220, a mesh layer 230, and a MAC layer 240. Notethat the mesh QoS architecture 200 may include more or less than theabove components. The mesh QoS architecture 200 improves the QoS byintelligently differentiating packets into different traffic and/orcontent categories. Based on the information, all packets arriving fromthe higher layer are classified into packet types according to thepacket traffic and content. A priority level is then given to a packetbased on its packet type. Packets are then distributed according totheir priority level and load condition. The mesh QoS architecture 200provides an optimized packet management at mesh driver layer to givepriorities to different traffics, handle multi-hop network traffic, anddifferentiate different quality levels of the streaming contents.

The application layer 210, the TCP/IP layer 220 and the MAC layer 240are the typical layers in a network. The application layer 210 mayinclude the application programs running at the local node. Packets maybe transferred from the application layer 210 to the mesh layer 230 viathe TCP/IP layer 220. The MAC layer 240 may have connectivity with othernodes in the network. It may also receive packets from other nodes whichare then pushed up to the mesh layer 230 to be processed. Theapplications that may be supported in the mesh QoS architecture 200 maybe any suitable applications. In one embodiment, these applications mayinclude the File Transfer Protocol (FTP), Digital Living NetworkAlliance (DLNA) supporting HyperText Transfer Protocol (HTTP) andReal-Time Streaming Protocol (RTSP), Server Message Block (SMB, orSamba), Network File System (NFS), Remote Procedure Call (RPC), Voiceover IP (VoIP), HTTP, etc.

The mesh layer 230 interfaces between the TCP/IP layer 220 and the MAClayer 240. It may receive packets from the application layer 210 via theTCP/IP layer 220 and send/transmit the packets within the local node ina local traffic. It may receive packets from the MAC layer 240 fromother nodes 245 and forward the packets to one of the other nodes 245 ina forwarding traffic. The mesh layer 230 may include a trafficrecognition and packet classifier 232, a queue manager 234, and ascheduler 236. The mesh layer 230 may include more or less than theabove components. Any of these components may be implemented byhardware, software, firmware, or any combination thereof. The classifier232, the queue manager 234, and the scheduler 236 are independent fromone another. They may operate sequentially, parallel, or in anoverlapping manner (e.g., pipelining)

The classifier 232 classifies or identifies the packets based on theapplications and/or the type of traffic into a plurality of packet typeshaving different priority levels. The classifier 232 may perform theclassification by examining the port identifiers, the source anddestination nodes, and the application that sends or receives thepacket. It may classify a packet into a packet type. The packet type maybe related to the traffic type such as local traffic or forwardingtraffic. Under this classification, a packet type may be a local type(for local traffic) or a forwarding type (for forwarding traffic). Thepacket type may also be related to the content of the packet or theapplication that transmits or receives the packet. Under thisclassification, a packet may be a control packet, a voice/audio packet,a high-quality video packet, a low-quality video packet, and abackground packet. A control packet is a packet that is used for controlfunctions such as mesh discovery, routing, etc. A voice/audio packet isa packet that is used for voice and/or audio such as Voice over IP(VoIP). A high-quality packet is a packet used for high-quality videostreams such as high definition (HD) or high-resolution video, such as1080 progressive/interlaced (P/I), 720 P/I, and 480 P/I. A low-qualitypacket is a packet used for low-quality video streams such as standarddefinition (SD) video or lower resolution video. A background packet isa packet used for background traffic such as meta data, web traffic,etc. Under this classification, a packet type may be a control type, avoice/audio type, a high-quality video type, a low-quality video type,and a background type, corresponding to the control packet, thevoice/audio packet, the high-quality video packet, the low-quality videopacket, and the background packet, respectively.

The classification may combine both the traffic type and the contenttype. In one embodiment, the traffic type includes two types: local typeand forwarding type. The content type includes five types: the controltype, the voice/audio type, the high-quality video type, the low-qualityvideo type, and the background type. Accordingly, a packet may be anyone of the ten packet types. It is contemplated that the number ofclassification types may be more or less than the above types dependingon the characteristics of the network, the network traffic, theapplications, and the contents.

The queue manager 234 performs queue management for mesh QoS in theWHMN. The queue manager 234 manages the outbound packets that arereceived from the TCP/IP layer 220 or the inbound packets (for self orforwarding) from the MAC layer 240. The queue manager 234 maintain anumber of buffers, or queues, tailored according to the packet types asclassified by the classifier 232. Each of the buffers may be tagged witha priority level based on the packet type. The queue manager 234processes the packets according to the priority level using a schedulingpolicy as provided by the scheduler 236.

The scheduler 236 schedules processing the buffers storing the packets.It may schedule distributing the queued packets from the plurality ofpacket queues based on the priority levels according to a schedulingpolicy. It may determine when the packets in the buffers are retrievedand sent to the destination nodes. In one embodiment, the scheduler usesa priority-based weighted round-robin scheduling policy to go through,or visit, the buffers. In general, the priority-based weightedround-robin scheduling policy starts with the buffer having the highestpriority level and then goes through the buffers according to thepriority level until it reaches the buffer having the lowest prioritylevel. After it processes the lowest priority buffer, it returns back tothe highest priority buffer and continues the process. The scheduler 236provides the queue manager 234 with information to retrieve the packetsfrom the buffers. This information may include which buffer is to beretrieved and the number of packets to be retrieved from a buffer. Ingeneral, the higher priority a buffer has, the more packets areretrieved from that buffer. The amount of packets to be retrieved fordistribution depends on the load condition of the buffer and isdynamically calculated. This calculation may be based on the networktraffic and the size of the buffer. To prevent buffer stalling orstarvation, the scheduler 236 employs a starvation prevention policy toallow low priority buffers receive service.

FIG. 3 is a flowchart illustrating a process 300 to provide a QoS forthe mesh network according to one embodiment.

Upon START, the process 300 interfaces between an upper layer and alower layer in a multi-hop mesh network to receive and transmit packetsfrom and to a local node and a remote node (Block 310). The upper layermay be the application layer 210 or the TCP/IP layer 220 shown in FIG.2.

Next, the process 300 classifies the received packets into a pluralityof packet types having different priority levels (Block 320). Then, theprocess 300 manages a plurality of buffers organized according to thepacket types (Block 330). The plurality of buffers stores the classifiedpackets based on the packet types. Then, the process 300 schedulesdistributing the packets from the plurality of buffers based on thepriority levels according to a scheduling policy (Block 340). Theprocess 300 is then terminated.

Traffic Recognition and Packet Classifier:

FIG. 4 is a diagram illustrating the traffic recognition and packetclassifier 232 shown in FIG. 2 according to one embodiment. Theclassifier 232 includes an extractor 410 and a packet classifier 420.The classifier 232 may include more or less than the above components.

The extractor 410 extracts a port identifier 425 in a transport layerheader 415 of a packet having a packet type associated with a prioritylevel. The packet is transmitted from an application according to anetwork protocol in a multi-hop mesh network having a local node and aremote node as described above. In the mesh network, the network-basedapplications follow certain pre-defined protocols (e.g., DLNA, Samba,NFS) which use common Transmission Control Protocol (TCP) or UserDatagram Protocol (UDP) ports for control set-up and negotiation ofports used for transmission of actual data packets. The transport layerheader 415 contains the port identifier 425 for traffic recognitionwhich identifies the port associated with the data packet beingtransmitted. The port identifier 425 may include a port number, the IPaddress that the port is associated with, and the communicationprotocol. The port identifier 425 may identify one of or both of thesource and destination ports for the application.

The packet classifier 420 includes a pre-defined port list 430, adynamic port table 440, an application header 450, an analyzer 460, andan updater 470. The packet classifier 420 classifies the packet into thepacket type using one of the pre-defined port list 430, the dynamic porttable 440, and the application header 450 of the application. Thepre-defined port list 430 is a list of the port identifiers of the portsthat have been pre-defined or designated for specific applications. Theport identifier may be a port number or a port label. Therefore, oncethe port identifier is known to be in the pre-defined port list 430, thetype of application or packet using the port identifier is knownimmediately. The packet classifier 420 then classifies the packet intothis known packet type. If the port identifier 425 is not in thepre-defined port list 430, then the dynamic port table 440 is used next.The dynamic port table 440 contains the list of the port identifiers andtheir associated packet types, application types, or priority levels aspreviously discovered or detected for the currently active sessions. Thetraffic recognition and packet classifier 232 analyzes packets comingfrom both the upper layer (e.g., the IP layer 220 shown in FIG. 2) andlower layer (e.g., the MAC layer 240 shown in FIG. 2). The controlpackets for common multimedia applications used for port negotiation areusually two-way communication and thus can be analyzed by the classifier232 for maintaining the dynamic port table 440. The dynamic port table440 is constantly updated and dynamically changed to reflect the currentstatus of the use of the ports for packet transmission. The dynamic porttable 440 is then searched to determine if it contains the extractedport identifier 425. If it does, then the packet type, application type,or priority level associated with the port identifier 425 is retrievedfrom the dynamic port table 440 and the packet classifier 420 classifiesthe packet into the corresponding packet type in the dynamic port table440. If, however, the dynamic port table 440 does not contain theextracted port identifier 425, then it means that the packet type or theapplication type has not yet been identified. To identify the packettype or the application type, the analyzer 460 analyzes the applicationheader 450 of the application of the packet. This may be done byrecognizing the application type and extracting the dynamic data portinformation. For example, this may be done by opening the applicationpacket and identify the session type based on the application header450. For example, the HTTP and SSDP control packets for the DLNA may becaptured to identify the DLNA streaming type. Once the packet type hasbeen identified, the updater 470 updates the dynamic port table 440 toinclude the extracted port identifier 425 together with the detected oridentified packet type or application type. Any other port identifierthat matches the port identifier 425 will now be associated with thenewly detected or identified packet type or application type. Theupdater 470 may also remove a port identifier in the dynamic port table440 if the application that uses it is no longer transmitted through thenetwork or when the connection of the application session is closed.

FIG. 5 is a flowchart to illustrate a process 500 to classify a packetaccording to one embodiment.

Upon START, the process 500 extracts a port identifier in a transportlayer header of a packet having a packet type associated with a prioritylevel (Block 510). The port identifier may be a port number or a portlabel. The packet is transmitted from or to an application according toa network protocol in a multi-hop mesh network having a local node and aremote node.

Next, the process 500 classifies the packet into the packet type usingone of a pre-defined port list, a dynamic port table, and an applicationheader of the application (Block 520). The process 500 is thenterminated.

FIG. 6 is a flowchart to illustrate the process 520 shown in FIG. 5 toclassify a packet according to one embodiment. Note that the process 520shown in FIG. 6 may follow the process 520 shown in FIG. 7.

Upon START, the process 520 assigns the packet type to a type of service(TOS) field in a network header such as the IP header defined for theport identifier (Block 610) and is then terminated. Since the TOS fieldin the IP header may be recognized by any IP QoS mechanism, theintegrity of the packet classification is maintained throughout the lifeof the packet in the network. For example, if the packet is forwarded toa gateway that is outside the mesh, non-mesh routers may still recognizethe classification and may assign priority level to the packet tomaintain consistent QoS service. Furthermore, inside the mesh network,packets may be forwarded via multiple hops, the mesh header may changebut the IP header containing the TOS field remains unchanged. Therefore,consistent QoS service may be guaranteed beyond one hop. As is known byone skilled in the art, if it is not desired to maintain consistent QoSbeyond the mesh network, then the classification may be recorded in amesh header.

FIG. 7 is a flowchart to illustrate the process 520 shown in FIG. 5 toclassify a packet according to one embodiment.

Upon START, the process 520 determines if the port identifier belongs toa pre-defined port list (Block 710). If so, the process 520 classifiesthe packet to the packet type associated with the port identifier in thepre-defined port list (Block 720) and is then terminated. Otherwise, theprocess 520 searches the dynamic port table for the port identifier(Block 730). Then, the process 520 determines if the dynamic port tablecontains the port identifier (Block 740). If so, the process 520classifies the packet into the packet type associated with the portidentifier in the dynamic port table (Block 750) and is then terminated.Otherwise, the process 520 analyzes the application header to identifythe packet type (Block 760). This may be done by recognizing theapplication type and extracting the dynamic data port information. Then,the process 520 classifies the packet into the packet type identifiedfrom the application header (Block 770). Next, the process 520 updatesthe dynamic port table to include the port identifier (Block 780) and isthen terminated. Note that the process 520 shown in FIG. 7 may befollowed by the process 520 shown in FIG. 6.

FIG. 8 is a flowchart to illustrate the process 760 shown in FIG. 7 toanalyze the application header according to one embodiment.

Upon START, the process 760 captures a control packet belonging to acurrent application session to identify a session type or a streamingtype (Block 810). Next, the process 760 recognizes the network protocol(Block 820). The recognized network protocol may be one of a FileTransfer Protocol (FTP), a Digital Living Network Alliance (DLNA)protocol, a HyperText Transfer Protocol (HTTP), a Real-Time StreamingProtocol (RTSP), a Server Message Block (SMB, or Samba) protocol, aNetwork File System (NFS) protocol, a Remote Procedure Call (RPC)protocol, and a Voice over IP (VoIP) protocol. In addition, the filetypes may also be recognized. For example, the file types transferred byDLNA application may include mpg, mpeg, mp4, avi, wmv, mov, wma, mp3,jpg, xml, etc. The process 760 is then terminated.

FIG. 9 is a flowchart to illustrate the process 780 shown in FIG. 7 toupdate the dynamic port table according to one embodiment.

Upon START, the process 780 associates the priority level to the portidentifier (Block 910). By virtue of this association, any other portidentifiers that match the combination of this port identifier have thesame priority level. Next, the process 780 removes the port identifierfrom the dynamic port table when a connection of the application sessionis closed (Block 920). The process 780 is then terminated.

Queue Manager:

FIG. 10 is a diagram illustrating the queue manager 234 shown in FIG. 2according to one embodiment. The queue manager 234 includes a receiver1005, an enqueuer 1010, and a plurality of buffers 1020. The queuemanager 234 may include more or less than the above components.

The receiver 1005 receives a packet from an upper layer (e.g., theTCP/IP layer 220 shown in FIG. 2) or a lower layer (e.g., the MAC layer240 shown in FIG. 2) in a multi-hop mesh network. The packet has apacket type classified by the classifier 232 (FIG. 2). The receiver 1005may be an interface to the classifier 232. It may be a buffer, a datasteering circuit, or any structure or module that passes the classifiedpacket to the enqueuer 1010. The enqueuer 1010 enqueues, deposits, orwrites the received packet into one of the plurality of buffers 320using the classification made by the classifier 232. For example, theenqueuer 1010 may read the TOS field of the corresponding IP header.

The buffers 1020 are organized according to the packet type or thepacket priority level. The buffers 1020 include N buffers, or queues,that correspond to N different packet types. It is contemplated that thenumber of buffers depends on the number of different packet types asclassified by the classifier 232 (FIG. 2). In one embodiment, the totalnumber of packet types is ten including the traffic type and the contenttype. The buffers 1020 include a local (LCL) buffer 1040 and aforwarding (FWD) buffer 1050 corresponding to the local type and theforwarding type, respectively. When the content type is combined withthe traffic type, each of the local buffer 1040 and forwarding buffer1050 includes five buffers for five different content types. They are acontrol (CTRL) buffer, a voice/audio (VO) buffer, a high-quality video(VH) buffer, a low-quality video (VL) buffer, and a background (BK)buffer corresponding to the control type, the voice/audio type, thehigh-quality video type, the low-quality video type, and the backgroundtype, respectively. The local buffer 1040 includes a BK buffer 1041, aVL buffer 1042, a VH buffer 1043, a VO buffer 1044, and a CTRL buffer1045. Similarly, the forwarding buffer 1050 includes a BK buffer 1051, aVL buffer 1052, a VH buffer 1053, a VO buffer 1054, and a CTRL buffer1055.

Each of the buffers 1020 is given a priority level and a weight valueaccording to its type. The priority level indicates the order in whichthe scheduler 236 goes through the buffers 1020 in a variableround-robin manner. The weight value provides a quantitative measure ofthe amount of packets to be retrieved from each buffer. In general, thehigher priority level, the more packets are retrieved from the buffer.In general, the forwarding type have the priority level higher than thelocal type and the priority level decreases in order from the controltype to the voice/audio type, the high-quality video type, thelow-quality video type, and the background typee. Accordingly, the CTRLbuffer has the highest priority, followed by the VO buffer, the VHbuffer, the VL buffer, and the BK buffer in that order. For the samecontent type, the forwarding buffer 1050 has a higher priority than thelocal buffer 1040. For example, the CTRL buffer 1055 has a highestpriority level. The VO buffer 1054 has a higher priority level than theVO 1044 and the VH 1053. The VO buffer 1044 in the local buffer 1040 hasa higher priority level than the VH 1053 in the forwarding buffer 1050.Table 2 shows the priority level and the weight values for the buffers1020.

TABLE 2 Priority level and weight values for the buffers 1020 shown inFIG. 10 Priority Buffer Traffic Type Buffer name Level Weight Q[LCL][BK]Local BK 341 0 W₁ Q[LCL][VL] Local VL 342 2 W₂ Q[LCL][VH] Local VH 343 4W₃ Q[LCL][VO] Local VO 344 6 W₄ Q[LCL][CTRL] Local CTRL 345 8 W₅Q[FWD][BK] Forwarding BK 351 1 W₆ Q[FWD][VL] Forwarding VL 352 3 W₇Q[FWD][VH] Forwarding VH 353 5 W₈ Q[FWD][VO] Forwarding VO 354 7 W₉Q[FWD][CTRL] Forwarding CTRL 355 9 W₁₀

In Table 2, the higher the value of the priority level, the higher thepriority is. The weight values W_(i)'s represent the number of packetsto be retrieved for the buffers. The exact number depends on the loadcondition of each buffer as dynamically calculated by the scheduler 236(FIG. 2). In one embodiment, the control buffers (e.g., CTRL 1055 and1045) are emptied first before going to the data buffers (e.g., VO 1054,VH 1053, VO 1044, VH 1043, etc.). The data buffers are those buffersassociated with the content type. Within the data buffers, those havinghigher priority level have higher weight values.

The buffers 1020 may be implemented in any suitable methods. In oneembodiment, they are implemented as circular static arrays forefficiency and delay reduction. The size of each buffer is large enoughto handle the most demanding scenarios. It may range from a fewkilobytes (KBs) to several megabytes (MBs). However, there may beextreme conditions, or exceptions, where the number of packets exceedsthe buffer capacity. In these rare circumstances, the packets may bedropped or become lost.

By discriminating different types of traffic and different types ofstreaming contents such as HD and SD, the queue manager 234 provides anefficient and enhanced QoS for mixed applications. The queue manager 234processes the packets based on their priority level assigned accordingto their type. In addition, the queue manager 234 is designed to workwith multiple hop distributed networks. It also works independently ofexisting QoS features at the application layer 210 or the MAC layer 240.It does not interfere with existing classification mechanism such as theclassification using the Type of Service (TOS) bit in the IP packet. Itprovides exception handling when buffer capacity is exceeded. It usescircular static arrays for fast processing time to reduce packet delays.It prevents starvation for low priority packets.

FIG. 11 is a flowchart illustrating a process 1100 to perform queuemanagement according to one embodiment.

Upon START, the process 1100 receives a packet from an upper layer or alower layer in a multi-hop mesh network (Block 1110). The packet has apacket type classified by a classifier such as the classifier 232 (FIG.2). Next, the process 1100 enqueues the received packet into one of aplurality of buffers organized according to the packet type (Block 1120)such as shown in FIG. 3. The process 1100 is then terminated.

FIG. 12 is a flowchart illustrating the process 1110 shown in FIG. 11 toreceive according to one embodiment.

Upon START, the process 1110 receives the packet from a local node fromthe upper layer or from a remote node in the multi-hop mesh network fromthe lower layer (Block 1210). The packet type may be a local type forlocal traffic within the local node or a forwarding type for forwardingtraffic to the remote node. The packet type may be further one of acontrol type, a voice/audio type, a high-quality video type, alow-quality video type, and a background type. The process 1110 is thenterminated.

FIG. 13 is a flowchart illustrating the process 1120 shown in FIG. 11 toenqueue according to one embodiment.

Upon START, the process 1120 deposits the packet into the plurality ofbuffers based on the packet type (Block 1310). The plurality of buffersincludes a local buffer and a forwarding buffer corresponding to thelocal type and the forwarding type, respectively.

Then, the process 1120 deposits the packet into the plurality of buffersbased on the further packet type (Block 1320). The plurality of buffersfurther includes a control buffer, a voice/audio buffer, a high-qualityvideo buffer, a low-quality video buffer, and a background buffercorresponding to the control type, the voice/audio type, thehigh-quality video type, the low-quality video type, and the backgroundtype, respectively. The process 1120 is then terminated.

Scheduler:

FIG. 14 is a diagram illustrating the scheduler 236 shown in FIG. 2according to one embodiment. The scheduler 236 includes a switchingmodule 1410, a buffer status 1415, and a dequeuer 1420. The scheduler236 may include more or less than the above components.

The switching module 1410 switches to the buffers 1020 in the queuemanager 236 to form connections for establishing data paths. Theswitching module 1410 may be a software switching structure to allow thedequeuer 1420 to access the buffers 1020. It provides visiting theplurality of buffers 1020 in a variable round robin manner. The roundrobin scheduling is variable in that the quantum time for visiting thebuffers and dequeuing may be variable depending on the status of thebuffers and their priority level. As described above, the buffers 1020store packets having packet types associated with priority levels andhaving buffer types according to the packet types. The packets aretransmitted from an application according to a network protocol in amulti-hop mesh network having a local node and a remote node.

The buffer status 1415 provides the status of the buffers. The status ofthe buffers may indicate the load of the buffers 1020 or the occupancyof the buffers. It may indicate if a buffer is empty. If a buffer isempty, then it may be skipped because there are no packets to retrieveand dequeue.

The dequeuer 1420 dequeues the buffers 1020 according to the buffertypes and using an amount dynamically weighted by the priority levelsassociated with the buffer types. As described above, each buffer isassigned a weight value. This weight value may be used to determine thenumber, or the amount, of packets to be dequeued. In one embodiment, theweight value of a buffer corresponds to its priority level. The dequeuer1420 delivers or retrieves a large amount of packets from buffers withhigher weight values and delivers or retrieves less number of datapackets from buffers that have lower weight values. The overallobjective is to reduce or minimize the delay introduced by the scheduler236 and at the same time ensures priority among the buffers.Furthermore, the dequeuer 1420 ensures that lower priority queues arenot starved or do not wait for a long time. The variable round robintraversing procedure prevents starvation.

The amount of packets to be dequeued at each buffer depends on itspriority level which is proportional or related to its weight value. ForN buffers, suppose the weight values are W₁, W₂, . . . , W_(N). At roundt, suppose the number of packets in each data buffer is P₁(t), P₂(t), .. . , P_(N)(t). Assume a pre-defined bucket with a token size of T. T isthe maximum number of packets that the dequeuer 1420 dequeues for eachround of visiting the buffers.

Let S _(i)(t)=0 if P _(i)(t)=0 and S _(i)(t)=1 otherwise.  (1)

The number, or amount, of packets to be dequeued at buffer j is definedas:

Q _(j)(t)=min{Pj(t),(T*W _(j) *S _(j)(t))/(Σ_(k=0) ^(N)(W _(k) *S_(k)(t))}  (2)

where min{A, B}=A if A<B and min{A, B}=B if B<A.

As an example, suppose node A sends video packet data and backgroundpacket data to node B. Node A enqueues the video packet data to bufferVH 1043 (FIG. 10) and background packet data to buffer BK 1041 (FIG.10). Suppose buffers VH 1043 and BK 1041 are assigned weights 3 and 1,respectively. Assume that T=8 and the numbers of packets stored inbuffers VH 1043 and BK 1041 are P_(VH)=18 and P_(BK)=5, respectively.Assume that the remaining buffers are empty. Using equations (1) and (2)above, the numbers of packets to be dequeued at buffers VH 1043 and BK1041 are:

Q _(VH)=Min{18,8*3/(3+1)}=Min{18,6}=6

Q _(BK)=Min{5,8*1/(3+1)}=Min{5,2}=2.

FIG. 15 is a flowchart illustrating a process 1500 to schedule accordingto one embodiment.

Upon START, the process 1500 visits a plurality of buffers in a variableround robin manner (Block 1510). The buffers store packets having packettypes associated with priority levels and having buffer types accordingto the packet types. The packets are generated for transmission from anapplication according to a network protocol in a multi-hop mesh networkhaving a local node and a remote node. Next, the process 1500 dequeuesthe buffers according to the buffer types and using an amountdynamically weighted by the priority levels associated with the buffertypes (Block 1520). The process 1500 is then terminated.

FIG. 16 is a flowchart illustrating the process 1510 to visit thebuffers according to one embodiment.

Upon START, the process 1510 determines the status of the buffer (Block1610). Next, the process 1510 determines if the buffer is empty (Block1620). If not, the process 1510 is terminated. Otherwise, the process1510 skips the buffer (Block 1630) and is then terminated. It iscontemplated that the process 1510 is repeated for all the buffers inthe queue manager according to the variable round robin scheduling.

FIG. 17 is a flowchart illustrating the process 1520 to dequeue thebuffers according to one embodiment.

Upon START, the process 1520 dequeues a control buffer completely (Block1710). As discussed above, the control buffer has the highest prioritybecause the packets in the control buffer are critical to maintain themesh network operations. Furthermore, control packets are usually smallin size and queued less frequently than data packets, typically at aconstant rate. Next, the process 1520 dequeues a data buffer afterdequeuing the control buffer completely (Block 1720). The process 1520dequeues the data buffers using an amount that is dynamicallycalculated. In one embodiment, the process 1520 retrieves the packetsfrom a buffer j using the amount calculated by

Q _(j)=min{Pj,(T*W _(j) *S _(j))/(Σ_(k=0) ^(N)(W _(k) *S _(k))}

wherein Pj is number of packets in the buffer j, W_(j) is a weight valueassigned to the buffer j according to priority level of the buffer j, Tis size of a pre-defined bucket, and S_(k)=0 if P_(k)=0 and S_(k)=1otherwise.

FIG. 18 is a diagram illustrating a processing system 1800 to performthe QoS according to one embodiment. The processing system 1800 may be atier-2 or tier-3 device in the WHMN. It may include a processor 1810, achips set 1820, a user interface 1825, a memory 1830, an interconnect1840, a mass storage medium 1850, a network interface card 1860, a radiotransceiver interface 1870, and an antenna 1880. The processing system1800 may include more or less than the above components.

The processor 1810 may be a central processing unit of any type ofarchitecture, such as processors using hyper threading, security,network, digital media technologies, single-core processors, multi-coreprocessors, embedded processors, mobile processors, micro-controllers,digital signal processors, superscalar computers, vector processors,single instruction multiple data (SIMD) computers, complex instructionset computers (CISC), reduced instruction set computers (RISC), verylong instruction word (VLIW), or hybrid architecture.

The chipset 1820 provides control and configuration of memory andinput/output (I/O) devices such as the memory 1830, the user interface1825, the mass storage medium 1850, and the network interface card 1860,and the radio transceiver 1870. The chipset 1820 may integrate multiplefunctionalities such as I/O controls, graphics, media,host-to-peripheral bus interface, memory control, power management, etc.

The user interface 1825 may include circuits and functionalities thatprovides interface to a user. This may include display control, entrydevice control, remote control, etc. The entry device or devices mayinclude keyboard, mouse, trackball, pointing device, stylus, or anyother appropriate entry device. The display device may be a television(TV) set, a display monitor, or a graphic output device. The displaytype may include any display type such as high definition TV (HDTV),cathode ray tube (CRT), flat panel display, plasma, liquid crystaldisplay (LCD), etc.

The memory 1830 stores system code and data. The memory 1830 istypically implemented with dynamic random access memory (DRAM), staticrandom access memory (SRAM), or any other types of memories includingthose that do not need to be refreshed, including read only memory(ROM), flash memories. In one embodiment, the memory 1830 may contain aQoS architecture 230 which may include the classifier 232, the queuemanager 234, and the scheduler 236. For simplicity, the QoS architecture230 is shown as part of the memory 1830. It may be downloaded, copied,or transferred from the mass storage medium 1850. It is contemplatedthat the QoS architecture 230, or any of its components may beimplemented by hardware, software, firmware, or any combination thereof.

The interconnect 1840 provides an interface for the chipset 1820 tocommunicate with peripheral devices such as the mass storage medium 1850and the NIC 1860. The interconnect 1840 may be point-to-point orconnected to multiple devices. For clarity, not all the interconnectsare shown. It is contemplated that the interconnect 1840 may include anyinterconnect or bus such as Peripheral Component Interconnect (PCI), PCIExpress, Universal Serial Bus (USB), and Direct Media Interface (DMI),etc. The mass storage medium 1850 may include compact disk (CD)read-only memory (ROM), memory stick, memory card, smart card, digitalvideo/versatile disc (DVD), floppy drive, hard drive, tape drive, andany other electronic, magnetic or optic storage devices. The massstorage device provides a mechanism to read machine-accessible media.The NIC 1860 provides interface to the various network layers in theWHMN such as the TCP/IP layer 220 and the MAC layer 240 as shown in FIG.2.

The radio transceiver interface 1870 may include analog and digitalcircuits to perform radio communication interface. It is connected tothe antenna 1880 to receive and transmit radio frequency (RF) signals.It may include analog and digital circuitries for down-conversion,filtering, analog-to-digital conversion, digital-to-analog conversion,up-conversion, wireless LAN interface, frequency multiplexing, etc. Theantenna 1880 may be any appropriate RF antenna for wirelesscommunication. In one embodiment, the antenna 1880 may be designed toaccommodate the frequency ranges as provided by the IEEE 802.11xstandards. The frequency range may be tuned to operate from 2.4 GHz to 5GHz.

Elements of one embodiment may be implemented by hardware, firmware,software or any combination thereof. The term hardware generally refersto an element having a physical structure such as electronic,electromagnetic, optical, electro-optical, mechanical,electro-mechanical parts, etc. A hardware implementation may includeanalog or digital circuits, devices, processors, applications specificintegrated circuits (ASICs), programmable logic devices (PLDs), fieldprogrammable gate arrays (FPGAs), or any electronic devices. The termsoftware generally refers to a logical structure, a method, a procedure,a program, a routine, a process, an algorithm, a formula, a function, anexpression, etc. The term firmware generally refers to a logicalstructure, a method, a procedure, a program, a routine, a process, analgorithm, a formula, a function, an expression, etc., that isimplemented or embodied in a hardware structure (e.g., flash memory).Examples of firmware may include microcode, writable control store,micro-programmed structure. When implemented in software or firmware,the elements of an embodiment may be the code segments to perform thenecessary tasks. The software/firmware may include the actual code tocarry out the operations described in one embodiment, or code thatemulates or simulates the operations. The program or code segments maybe stored in a processor or machine accessible medium. The “processorreadable or accessible medium” or “machine readable or accessiblemedium” may include any medium that may store or transfer information.Examples of the processor readable or machine accessible medium that maystore include a storage medium, an electronic circuit, a semiconductormemory device, a read only memory (ROM), a flash memory, an erasableprogrammable ROM (EPROM), a floppy diskette, a compact disk (CD) ROM, anoptical storage medium, a magnetic storage medium, a memory stick, amemory card, a hard disk, etc. The machine accessible medium may beembodied in an article of manufacture. The machine accessible medium mayinclude information or data that, when accessed by a machine, cause themachine to perform the operations or actions described above. Themachine accessible medium may also include program code, instruction orinstructions embedded therein. The program code may include machinereadable code, instruction or instructions to perform the operations oractions described above. The term “information” or “data” here refers toany type of information that is encoded for machine-readable purposes.Therefore, it may include program, code, data, file, etc.

All or part of an embodiment may be implemented by various meansdepending on applications according to particular features, functions.These means may include hardware, software, or firmware, or anycombination thereof. A hardware, software, or firmware element may haveseveral modules coupled to one another. A hardware module is coupled toanother module by mechanical, electrical, optical, electromagnetic orany physical connections. A software module is coupled to another moduleby a function, procedure, method, subprogram, or subroutine call, ajump, a link, a parameter, variable, and argument passing, a functionreturn, etc. A software module is coupled to another module to receivevariables, parameters, arguments, pointers, etc. and/or to generate orpass results, updated variables, pointers, etc. A firmware module iscoupled to another module by any combination of hardware and softwarecoupling methods above. A hardware, software, or firmware module may becoupled to any one of another hardware, software, or firmware module. Amodule may also be a software driver or interface to interact with theoperating system running on the platform. A module may also be ahardware driver to configure, set up, initialize, send and receive datato and from a hardware device. An apparatus may include any combinationof hardware, software, and firmware modules.

It will be appreciated that various of the above-disclosed and otherfeatures and functions, or alternatives thereof, may be desirablycombined into many other different systems or applications. Variouspresently unforeseen or unanticipated alternatives, modifications,variations, or improvements therein may be subsequently made by thoseskilled in the art which are also intended to be encompassed by thefollowing claims.

1. A method comprising: interfacing between an upper layer and a lowerlayer in a multi-hop mesh network to receive and transmit packets fromand to a local node and a remote node; classifying the received packetsinto a plurality of packet types having different priority levels;managing a plurality of buffers organized according to the packet types,the plurality of buffers storing the classified packets based on thepacket types; and scheduling distributing the packets from the pluralityof buffers based on the priority levels according to a schedulingpolicy.
 2. The method of claim 1 wherein interfacing comprises:receiving the packets from the local node or an application at the upperlayer.
 3. The method of claim 1 wherein interfacing comprises: receivingthe packets from the remote node at the lower layer.
 4. The method ofclaim 1 wherein interfacing comprises: transmitting the packets to thelocal node or an application at the upper layer.
 5. The method of claim1 wherein interfacing comprises: transmitting the packets to the remotenode at the lower layer.
 6. The method of claim 1 wherein the packettype is a local type for local traffic within the local node or aforwarding type for forwarding traffic to the remote node.
 7. The methodof claim 6 wherein the packet type is further one of a control type, avoice/audio type, a high-quality video type, a low-quality video type,and a background type.
 8. The method of claim 7 wherein the forwardingtype have the priority level higher than the local type.
 9. The methodof claim 7 wherein the priority level decreases in order from thecontrol type to the voice/audio type, the high-quality video type, thelow-quality video type, and the background type.
 10. An article ofmanufacture comprising: a machine-accessible storage medium includingdata that, when accessed by a machine, cause the machine to performoperations comprising: interfacing between an upper layer and a lowerlayer in a multi-hop mesh network to receive and transmit packets fromand to a local node and a remote node; classifying the received packetsinto a plurality of packet types having different priority levels;managing a plurality of buffers organized according to the packet types,the plurality of buffers storing the classified packets based on thepacket types; and scheduling distributing the packets from the pluralityof buffers based on the priority levels according to a schedulingpolicy.
 11. The article of manufacture of claim 10 wherein the datacausing the machine to perform interfacing comprise data that, whenaccessed by the machine, cause the machine to perform operationscomprising: receiving the packets from the local node or an applicationat the upper layer.
 12. The article of manufacture of claim 10 whereinthe data causing the machine to perform interfacing comprise data that,when accessed by the machine, cause the machine to perform operationscomprising: receiving the packets from the remote node at the lowerlayer.
 13. The article of manufacture of claim 10 wherein the datacausing the machine to perform interfacing comprise data that, whenaccessed by the machine, cause the machine to perform operationscomprising: transmitting the packets to the local node or an applicationat the upper layer.
 14. The article of manufacture of claim 10 whereinthe data causing the machine to perform interfacing comprise data that,when accessed by the machine, cause the machine to perform operationscomprising: transmitting the packets to the remote node at the lowerlayer.
 15. The article of manufacture of claim 10 wherein the packettype is a local type for local traffic within the local node or aforwarding type for forwarding traffic to the remote node.
 16. Thearticle of manufacture of claim 15 wherein the packet type is furtherone of a control type, a voice/audio type, a high-quality video type, alow-quality video type, and a background type.
 17. The article ofmanufacture of claim 16 wherein the forwarding type have the prioritylevel higher than the local type.
 18. The article of manufacture ofclaim 16 wherein the priority level decreases in order from the controltype to the voice/audio type, the high-quality video type, thelow-quality video type, and the background type.
 19. An apparatuscomprising: an interface between an upper layer and a lower layer in amulti-hop mesh network to receive and transmit packets from and to alocal node and a remote node; a classifier coupled to the interface toclassify the received packets into a plurality of packet types havingdifferent priority levels; a queue manager coupled to the classifier tomanage a plurality of buffers organized according to the packet types,the plurality of buffers storing the classified packets based on thepacket types; and a scheduler coupled to the queue manager to scheduledistributing the packets from the plurality of buffers based on thepriority levels according to a scheduling policy.
 20. The apparatus ofclaim 19 wherein the interface receives the packets from the local nodeor an application at the upper layer.
 21. The apparatus of claim 19wherein the interface receives the packets from the remote node at thelower layer.
 22. The apparatus of claim 19 wherein the interfacingtransmits the packets to the local node or an application at the upperlayer.
 23. The apparatus of claim 19 wherein the interfacing transmitsthe packets to the remote node at the lower layer.
 24. The apparatus ofclaim 19 wherein the packet type is a local type for local trafficwithin the local node or a forwarding type for forwarding traffic to theremote node.
 25. The apparatus of claim 24 wherein the packet type isfurther one of a control type, a voice/audio type, a high-quality videotype, a low-quality video type, and a background type.
 26. The apparatusof claim 25 wherein the forwarding type have the priority level higherthan the local type.
 27. The apparatus of claim 25 wherein the prioritylevel decreases in order from the control type to the voice/audio type,the high-quality video type, the low-quality video type, and thebackground type.